Re: [CAD_CAM_EDM_DRO] Calculating mechanical forces

Thanks Jon!

As for the forces, not sure. I have 0.5" roundways with twin bearing
pillow blocks, which are rated at 360# downward loading. Side loading
would be less. Unless I managed to rotate them 90* when I mount them,
hmm. Anyway, thanks again for the example.

Regards,
JJ

On 01-Aug-2005, at 23:03, Jon Elson wrote:

>
>>
>>
>> In a message dated 8/1/2005 7:27:09 PM Eastern Daylight Time,
>> johnatl@... writes:
>>
>> I'm looking for formulae for calculating the forces while machining
>> various materials.
>> For example, if I want to use roundways and linear bearings for my Y
>> axis,
>> and I want to cut mild steel with a 2" fly cutter at some SFPM, and
>> some feed per revolution,
>> I want to find the force on the Y axis. That way I can find the size
>> parts I need for
>> a certain capacity and a certain life span.
>>
>>
> The way I did this was to calculate the torque when spinning the
> cutter at
> the appropriate SFPM for steel and consuming the motor's rated HP at
> that speed. Then, I converted that torque to linear force at the
> radius of
> the cutter. A 2" diameter fly cutter would presumably have a 1" tip
> radius
> when set to exactly 2" dia, making the calculation easy. With HSS and
> mild steel,
> you run about 100 SFPM, or 190 RPM at 2" dia. Assuming a 1 Hp motor,
> this would deliver a torque of [550 ft-Lb/sec / ((190/60)(rev/sec) * 2
> Pi) ] =
> 27.6 Ft-Lb = 332 in-Lb. So, at a radius of one inch, the force on the
> cutter tip
> would be 332 Lbs! Think your round ways and linear bearings can keep
> the
> machine within it's tolerances with 332 Lbs of force? Well, maybe you
> have a
> smaller motor.
>
> Jon
>
>
>
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